The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
An engine combusts air and fuel within cylinders to generate torque. A fuel system injects fuel for the engine. A control module controls the fuel system to control fuel injection amount and timing. The control module selectively adjusts the amount of fuel provided to the engine based on signals from an exhaust gas oxygen (EGO) sensor located upstream from a catalyst in an exhaust system. The control module also selectively adjusts the amount of fuel provided to the engine based on signals from an EGO sensor located downstream from the catalyst.
For example only, when the upstream EGO sensor indicates that the exhaust is (fuel) rich, the control module may decrease the amount of fuel provided to the engine. Conversely, the control module may increase the amount of fuel provided to the engine when the exhaust is lean. Adjusting the amount of fuel provided to the engine based on the signals from the EGO sensors may, for example, modulate the air/fuel mixture combusted within the engine at approximately a desired air/fuel mixture (e.g., a stoichiometric mixture).